Nonlinear Regression Models of Multicomponent Interactions of Anhydropolyols with Aqueous Ammonium Ion by Carbon-13 Nuclear Magnetic Resonance

Article abstract of DOI:10.1021/j100246a035

The anhydropolyhydric alcohols 1,4-anhydroerythritol and 1,4- anhydrothreitol were synthesized from the corresponding tetratols via acid-catalyzed dehydration, under vacuum, using H⁺ ion exchange resin.Comparison of temperature-dependent 13C NMR chemical shifts i aqueous and nonaqueous solvents demonstrated a significant molecular association interaction between 1,4-anhydroerythritol and water.The chemical shifts of C(1) and C(2) of 1,4-anhydrothreitol and C(1) of 1,4-anhydroerythritol showed a linear increase with temperature but C(2) of 1,4-anhydroerythritol showed a decrease between ca. 0 and ca. 55 deg C followed by an increase from ca. 55 to ca. 100 deg C.A multiligand complex was shown between 1,4-anhydroerythritol, water, and ammonium ion.The stoichiometry of the interaction between 1,4-anhydroerythritol, water, and aqueous ammonium ion was determined by nonlinear regression analysis applied to data obtained from 13C NMR chemical shifts through variation of temperature, solvent activity, a_H2O(c,T), and solute activity, a_NH4Cl(c,T).A general model was constructed for the dependence of the 13C NMR chemical shifts upon temperature and the activities of the two ligand species.